This invention pertains to the technology of cartons generally formed of paperboard and capable of holding liquid products. Typical cartons have a core structural layer of paperboard providing the carton's strength and rigidity. A layer of aluminum foil is adhered to one surface of the paperboard and serves as a barrier layer against passage of contaminants into the package. Both outer surfaces of the paperboard/foil combination are then coated with heat sealable plastic. While a number of specific constructions are known, it is generally accepted practice to close the carton openings with seals wherein surfaces of the plastic which faces the interior of the carton are brought into face-to-face contact along opposing edges and sealed together, in most cases forming a fin. A typical carton is produced as Systempak, by Papeteries de Belgique in Belgium. A similar carton is produced by Tetra-Pak in Lund, Sweden. German Pat. No. 2,721,390 describes another similar carton wherein part of the paperboard is removed from one side of a longitudinal seam to reduce the possibility of product leakage from the carton bottom. This and similar cartons are believed to be produced by Jagenberg Werke AG, Dusseldorf, Germany. U.S. Pat. No. 3,998,378, assigned to Jagenberg Werke AG, teaches a specific configuration for the bottom construction. U.S. Pat. No. 4,185,765, teaches a specific seal and score line configuration in the top fin for opening the carton.
In cartons of the prior art known to the inventor, access to the product is obtained by cutting open the fin seal on the top of the carton and cutting away a portion of the spout. Most of the above-mentioned cartons suggest the use of scissors. One observed prior art sample had a line of dashed cut scores extending part way through (but not completely through) the paperboard layer along the base of the top fin. A cutting device was essential to opening the carton along that line.
While the use of a cutting device such as scissors is certainly functional, it is inconvenient, and it is not always practical to have a cutting device available. Further, in cutting away part of the spout, the functional utility of the spout is somewhat impaired.
Thus, the use of existing cartons is limited by the immediate availability of some means of cutting open the carton, and the utility of the opened carton in dispensing product is somewhat impaired by the opening process.
It is therefore an object of this invention to provide a liquid-tight pouring carton which can be opened without the use of a mechanical cutting device.
It is a further object of this invention to provide such a carton having a complete spout, which maximizes the functional utility of the spout, and thus the ease of pouring.
It is a particular object to provide an opening means which can be activated to open the carton by tearing the opening means on a predetermined and weakened line, the carton being fully sealed and capable of holding liquid until the opening means is activated.
Also contemplated is a blank suitable for erection into the liquid-tight carton of this invention.
A particular object is to provide a method of making the blank, and subsequently forming it into the carton.